In this analysis I will compare common trends when comparing all bloodlines side by side. If you would like to see more in depth comparisons of the bloodlines for a particular category please see below their bloodlines on their individual page.
Please do not limit the connections I make so that they are the only important connections within the bloodlines. Due to the sheer size of the Thoroughbred bloodline, hundreds of connections can be made, with all of them being significant, however I have described the connections I find to be the most prevalent and most noteworthy.
Please do not limit the connections I make so that they are the only important connections within the bloodlines. Due to the sheer size of the Thoroughbred bloodline, hundreds of connections can be made, with all of them being significant, however I have described the connections I find to be the most prevalent and most noteworthy.
The greatest trend seen when comparing the bloodlines side-by-side would be (1) the amount of inbreeding occurring within the “Breakdown” or “Mysterious Disappearance” horses and (2) amount of connections that can be made for these horses as well.
The only horse inbred within the Triple Crown winners is Seattle Slew in the 4th and 5th generations. There are three inbred horses occurring in the “Successful or Famous Racers” bloodline. Nearly all the inbreeding occurs in the 4th and 5th generations, allowing for more recent breeding to “undo” any negative traits that may have been unknowingly selected for within this inbreeding. Compared to 4 inbred horses, the “Breakdown” or “Mysterious Disappearance” bloodlines have 19 inbred horses on the sire sides and 8 on the dam sides. While this is not conclusive, this strongly suggests that the repeated selection of successful sires or dams within one bloodline is selecting for negative traits that are masked by the positive trait that the breeders were looking for. After the same horse appears in the bloodline on the sire and dam side, the genotypes of their offspring are going to become increasingly homozygous. Many negative qualities are controlled by recessive alleles, and after breeders unknowingly select for more homozygous horses, the recessive genes will become more common and will appear within the bloodline, showing the negative trait that could not be seen in their heterozygous parents. Because inbreeding occurs most in the breakdown horses, breeders of these horses have revealed recessively controlled traits, which could be coded for on genes that could influence injuries, bone structure, joint function or any other trait that could explain these deadly breakdowns.
Also seen within the “Breakdown” bloodline is the vast number of connections that could be made between the total of 15 horses (not including Black Gold). While some of the older horses born in the early or mid-1900’s cannot link so intricately with other horses, the horses born in the 2000’s are almost all seen within the web of “Breakdowns” or “Mysterious Disappearances.” This suggests that the “older” horses were more successful. Their bloodlines remained almost completely free of major inbreeding and they had distinct bloodlines that did not mingle. Native Dancer, Nasrullah and Fair Play did not have many common offspring, suggesting that breeders of those times did not inbreed their successful sires or dams, nor did they cross with other major bloodlines, keeping their horses “pure.” This can also be seen within the dam bloodlines, with Fairy Gold, Fairy Ray, Miss Disco and Gold Digger never sharing common offspring and Geisha only sharing 1 with Fairy Ray and 1 with Gold Digger. This cannot be said for the “Breakdown” or “Mysterious Disappearance” horses. Gold Digger and Geisha share 9 common offspring and Miss Disco and Geisha share 3. The Triple Crown Winners are not nearly as linked together. The major link can be seen for Affirmed, who is descended from Teddy, Sir Gallahad III, Gallant Fox, Native Dancer and War Admiral. This links him to 7 of the Triple Crown Winners through their descent from Teddy, Native Dancer or War Admiral. It is important to note that there has not been a Triple Crown winner for 35 years. Affirmed was the last winner in 1978.
The racehorses today are so intricately wound between different bloodlines, with the same horse appearing multiple times within their bloodline. Instead of Triple Crown Winners, we see breakdowns and injuries on the racetracks across the nation. According to the bloodlines I have constructed, there may be a genetic reason for these breakdowns. There is most likely a strong pattern of inheritance that can be seen when comparing the “good” horses with the “bad” horses. The horses that have received positive genes that could give them stronger bodies, faster speeds and greater endurance can be seen because they have very little, if any, inbreeding, allowing for the strong qualities to stay prominent and the negative qualities to stay masked or dormant. After the inbreeding and the increased breeding between successful sires and dams, possible genes that could code for “breakdowns” and injuries appear because of the increased homozygosity. This is not the only conclusion that could be made. Other factors can explain why breakdowns are more common today and why we have not had a Triple Crown winner for 35 years. Steroids, drugs, training techniques, track surfaces, nutrition or the evolving change of the Thoroughbred body (seen when comparing the conformation of older horses to new horses) could be other explanations. While more research is required to determine the true cause of breakdowns and detrimental injuries to these incredible racers, it is impossible to ignore the patterns discussed here and the patterns I also discuss after the bloodlines for each “type” of horse.
The only horse inbred within the Triple Crown winners is Seattle Slew in the 4th and 5th generations. There are three inbred horses occurring in the “Successful or Famous Racers” bloodline. Nearly all the inbreeding occurs in the 4th and 5th generations, allowing for more recent breeding to “undo” any negative traits that may have been unknowingly selected for within this inbreeding. Compared to 4 inbred horses, the “Breakdown” or “Mysterious Disappearance” bloodlines have 19 inbred horses on the sire sides and 8 on the dam sides. While this is not conclusive, this strongly suggests that the repeated selection of successful sires or dams within one bloodline is selecting for negative traits that are masked by the positive trait that the breeders were looking for. After the same horse appears in the bloodline on the sire and dam side, the genotypes of their offspring are going to become increasingly homozygous. Many negative qualities are controlled by recessive alleles, and after breeders unknowingly select for more homozygous horses, the recessive genes will become more common and will appear within the bloodline, showing the negative trait that could not be seen in their heterozygous parents. Because inbreeding occurs most in the breakdown horses, breeders of these horses have revealed recessively controlled traits, which could be coded for on genes that could influence injuries, bone structure, joint function or any other trait that could explain these deadly breakdowns.
Also seen within the “Breakdown” bloodline is the vast number of connections that could be made between the total of 15 horses (not including Black Gold). While some of the older horses born in the early or mid-1900’s cannot link so intricately with other horses, the horses born in the 2000’s are almost all seen within the web of “Breakdowns” or “Mysterious Disappearances.” This suggests that the “older” horses were more successful. Their bloodlines remained almost completely free of major inbreeding and they had distinct bloodlines that did not mingle. Native Dancer, Nasrullah and Fair Play did not have many common offspring, suggesting that breeders of those times did not inbreed their successful sires or dams, nor did they cross with other major bloodlines, keeping their horses “pure.” This can also be seen within the dam bloodlines, with Fairy Gold, Fairy Ray, Miss Disco and Gold Digger never sharing common offspring and Geisha only sharing 1 with Fairy Ray and 1 with Gold Digger. This cannot be said for the “Breakdown” or “Mysterious Disappearance” horses. Gold Digger and Geisha share 9 common offspring and Miss Disco and Geisha share 3. The Triple Crown Winners are not nearly as linked together. The major link can be seen for Affirmed, who is descended from Teddy, Sir Gallahad III, Gallant Fox, Native Dancer and War Admiral. This links him to 7 of the Triple Crown Winners through their descent from Teddy, Native Dancer or War Admiral. It is important to note that there has not been a Triple Crown winner for 35 years. Affirmed was the last winner in 1978.
The racehorses today are so intricately wound between different bloodlines, with the same horse appearing multiple times within their bloodline. Instead of Triple Crown Winners, we see breakdowns and injuries on the racetracks across the nation. According to the bloodlines I have constructed, there may be a genetic reason for these breakdowns. There is most likely a strong pattern of inheritance that can be seen when comparing the “good” horses with the “bad” horses. The horses that have received positive genes that could give them stronger bodies, faster speeds and greater endurance can be seen because they have very little, if any, inbreeding, allowing for the strong qualities to stay prominent and the negative qualities to stay masked or dormant. After the inbreeding and the increased breeding between successful sires and dams, possible genes that could code for “breakdowns” and injuries appear because of the increased homozygosity. This is not the only conclusion that could be made. Other factors can explain why breakdowns are more common today and why we have not had a Triple Crown winner for 35 years. Steroids, drugs, training techniques, track surfaces, nutrition or the evolving change of the Thoroughbred body (seen when comparing the conformation of older horses to new horses) could be other explanations. While more research is required to determine the true cause of breakdowns and detrimental injuries to these incredible racers, it is impossible to ignore the patterns discussed here and the patterns I also discuss after the bloodlines for each “type” of horse.
For more information, please observe some of the differences I acknowledge when comparing conformation of horses when looking through each horse’s biography and conformation analysis. Please pay close attention to the descriptions of each horse’s neck and the relationship between body size and thickness of their legs.
Also, to see a conformation comparison between U.S. and English Thoroughbreds, a separate page exists under the “Genetics” tab. On this page horses from 3 years are compared, with each horse winning either the first race of the U.S. or English Triple Crown.
Also, to see a conformation comparison between U.S. and English Thoroughbreds, a separate page exists under the “Genetics” tab. On this page horses from 3 years are compared, with each horse winning either the first race of the U.S. or English Triple Crown.